Field
Embodiments of the present disclosure generally relate to an apparatus and method for processing multiple substrates, such as semiconductor wafers, and more particularly, to an apparatus and method of curing a dielectric material disposed on multiple substrates.
Description of the Related Art
Semiconductor device geometries have dramatically decreased in size since their introduction several decades ago. Modern semiconductor fabrication equipment routinely produce devices with 32 nm, 28 nm and 22 nm feature sizes, and new equipment is being developed and implemented to make devices with even smaller geometries. The decreasing feature sizes result in structural features on a device having decreased spatial dimensions. Consequently, the widths of structures on the device (e.g., gaps, trenches and the like) can narrow to a point where the aspect ratio of gap depth to gap width becomes so high that filling such gaps with dielectric material is problematic. This is because the dielectric material being deposited is prone to a phenomenon known as “pinch-off,” in which the entry region of a high aspect ratio gap or other structure may close before bottom-up fill has been completed, leaving voids or weak spots within the structure.
Over the years, many techniques have been developed to either avoid pinch-off or to “heal” voids or seams that have been formed as a result of pinch-off. One approach has been to start with highly flowable precursor materials that may be applied in a liquid phase to a spinning substrate surface (e.g., SOG deposition techniques). These flowable precursors can flow into and fill very small substrate gaps without forming voids or weak seams. However, once these highly flowable materials are deposited, they have to be hardened into a solid dielectric material.
In many instances, the hardening process includes a heat treatment to remove volatile components from the deposited material that are necessary to make the initially deposited film flowable. After removal of these components, a hardened and dense dielectric material with high etch resistance, such as silicon oxide, is left behind.
The flowability of such films may result from various chemical components included in the films, but hardening and densifying the films through removal of these same chemical components is almost uniformly beneficial across the suite of flowable deposition techniques. These hardening and densifying processes can be time-consuming. Thus, there is a need for new post-processing techniques and apparatus for densifying the wide variety of flowable films that are currently available or are under development. This and other needs are addressed in the present disclosure.